Nowadays there are many photos circulated on the internet for communications of all purposes, and photos can be easily edited with many handy software programs and applications with various effect filters, for example, Photoshop, GIMP or Instagram. For convenience of description, an edited photo is called a picture thereinafter. That is, a photo is a picture taken with a camera and is an exact representation of the original object, e.g. a person, or a scene etc. All photos are pictures. But besides photos, pictures include drawings, paintings or computer-generated images as well. Under this clarification, an edited photo may not be a photo any more, instead, it can only be called a picture.
For entertainment or for misinformation purposes, many internet users would present manipulated pictures as photos. The manipulation is made possible to common users by above-mentioned handy software programs and applications with various effect filters. Therefore, often times it is difficult, if possible at all, for a viewer to tell whether a picture is an authentic photo or has been manipulated or altered. When the viewer can't tell, he or she risks getting wrong information or misunderstanding what the picture represents.
For example, FIG. 1 illustrates a picture that was altered to depict Hurricane Sandy. Obviously, it is fake. However, if someone believed the picture served for entertainment purposes or for misinformation purposes, he might panic, or might take wrong actions and suffer unnecessary loss or get hurt. Also the fact that someone being unable to tell whether a picture is authentic can severely hurt the trust for the internet. Yet there is no solution provided for one to tell a picture presented is an authentic photo or not.